This invention relates generally to circuits and, more specifically, relates to autonomic compensation for degradation of circuits such as caused by bias-temperature instability and/or hot carrier injection, over the lifetime of the circuits.
This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise explicitly indicated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section. Abbreviations and acronyms used in this document and/or the drawings are defined below, prior to the claims.
Degradation of FETs due to bias-temperature instability (BTI) and hot-carrier injection (HCl) is inevitable in CMOS technology. FET degradation leads to performance reduction because the threshold voltage increases. In today's common practice, static, higher-than-needed operating voltage (a so-called ‘guard-band’) is used to allow for correct operation throughout life of product based on predicted life-time degradation. Since voltage increases degradation, this actually slightly accelerates the problem.